MAGETWO-93808: [Forwardport] Catalog EAV table getting called instead of flat table on top menu when flat is enabled

Author: slopukhov

app/code/Magento/Catalog/Model/ResourceModel/Category/Flat/Collection.php

@@ -12,6 +12,7 @@
 use Magento\Framework\Model\ResourceModel\Db\AbstractDb;
 use Psr\Log\LoggerInterface as Logger;
 use Magento\Store\Model\StoreManagerInterface;
+use Magento\Store\Model\ScopeInterface;
 
 /**
  * Catalog category flat collection
@@ -48,12 +49,20 @@ class Collection extends \Magento\Framework\Model\ResourceModel\Db\Collection\Ab
      */
     protected $_storeId;
 
+    /**
+     * Core store config
+     *
+     * @var \Magento\Framework\App\Config\ScopeConfigInterface
+     */
+    private $scopeConfig;
+
     /**
      * @param \Magento\Framework\Data\Collection\EntityFactory $entityFactory
      * @param Logger $logger
      * @param FetchStrategyInterface $fetchStrategy
      * @param ManagerInterface $eventManager
      * @param \Magento\Store\Model\StoreManagerInterface $storeManager
+     * @param \Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig
      * @param \Magento\Framework\DB\Adapter\AdapterInterface $connection
      * @param AbstractDb $resource
      */
@@ -63,10 +72,12 @@ public function __construct(
         FetchStrategyInterface $fetchStrategy,
         ManagerInterface $eventManager,
         StoreManagerInterface $storeManager,
+        \Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig,
         \Magento\Framework\DB\Adapter\AdapterInterface $connection = null,
         AbstractDb $resource = null
     ) {
         $this->_storeManager = $storeManager;
+        $this->scopeConfig = $scopeConfig;
         parent::__construct($entityFactory, $logger, $fetchStrategy, $eventManager, $connection, $resource);
     }
 
@@ -387,4 +398,21 @@ public function setPage($pageNum, $pageSize)
         $this->setCurPage($pageNum)->setPageSize($pageSize);
         return $this;
     }
+
+    /**
+     * Add navigation max depth filter
+     *
+     * @return $this
+     */
+    public function addNavigationMaxDepthFilter()
+    {
+        $navigationMaxDepth = (int)$this->scopeConfig->getValue(
+            'catalog/navigation/max_depth',
+            ScopeInterface::SCOPE_STORE
+        );
+        if ($navigationMaxDepth > 0) {
+            $this->addLevelFilter($navigationMaxDepth);
+        }
+        return $this;
+    }
 }